Barrel Profile ???? (AR)

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dsmithla

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I know this is a perception based kind of question and everybody's mileage kinda varies here, but how much difference in handling/weight should I expect between a 16" AR Carbine (medium length gas system, not that it matters) with a government profiled barrel, versus the same rifle with a medium profiled barrel?


I thinking about issues such as balance and quickness of the weapon. What advantages (if any) would the medium contour barrel have over the government profile anyway?

Thanks,

Dave
 
Do you mean government profile vs. HBAR?
If so, I have found a huge difference in weight and feel. The government profile (a 1970 M16 upper) is much lighter than my A2 with an HBAR or my carbine with an HBAR.
The government profile is supposed to be less accurate, especially after it heats up. Whether that is true or not, I don't know.
 
yea you'd have to do a bit of shootin b4 the hbar would show its colors.
you'd be fatigued slightly sooner if you had to lug the addl weight of a heavier gun.
that being said, i wouldnt have a pencil bbl gun
my 6920 os med profile, and my sporter match hbar is a blast.
 
Naw, Medium

Naw there's a Medium profile that's somewhere between HBAR and government.

As I think about it, the government profile barrel is on the government rifles (duh), like the M4 and the M16A4 which are being fired a whole lot more than I'll ever be likely to need, and I think they're holding up acceptably.


I was just wondering if for practical (plinking/social) purposes the slightly heavier barrel was asset or liability (not HBAR though, I'm thinking that would be TOO heavy and cost me maneuverability if I ever REALLY needed the rifle).

This is representative of what I'm talking about:

CMMG 16 M4 A1 SOCOM Barrel
New production 16” M4 A1 SOCOM barrels. Features include medium contour, parkerizing under “F” marked forged front sight base, chrome lined chamber and bore, MP testing, 5.56mm chambering, 1/7” twist, M4 barrel extension, mil-spec parkerizing, drilled gas port, step down for grenade launcher, and standard 1/2x28 threads. Included with barrel is A2 sight assembly, M-4 handguard cap and barrel nut. Barrels are engraved “CMMG MPC 5.56 NATO 1/7”.

Dave
 
A "medium profile" barrel is usually a proprietary profile and differs from manufacturer to manufacturer. The CMMG medium profile (which I have) is comparable in weight to an M4 barrel. It is slightly heavier; but it will feel much more like an M4 than an HBAR. I think it is around 2.2lbs.

A government profile midlength will be lighter (more area covered by handguard means more area with lighter profile) and is actually a smidgen lighter than an M4 usually in 16" lengths.

I haven't seen heating problems with either barrel; but I haven't done seven mag dumps followed by shooting for groups either. Both profiles will do well enough while hot that you won't notice it unless you are engaged in benchrest shooting AND are a pretty good shot.
 
So how much lighter is a govt. profile 16" middy than an HBAR anyway? I've looked around the net for this info before, but have never been able to find a definitive answer.
 
FWIW, Colt Defense's site lists the weights for the 6920 and the 6721, which are essentially the same rifle except for the HBAR on the 6721 (handguards and front swivel mounts are different too, but I imagine that weight difference is negligible). The 6920 weighs in at 5.95# while the 6721 is 7#.
 
Thank you MMcfpd, that helps. With the extra length of the handguard area on a mid-length, there's probably another quarter pound or so which can be shaved off then. I guess that means it would be well worth a barrel upgrade before adding another 12 ounces worth of free float to my middy..
 
I have a Colt 6721 HBar, 1:9, A2 stock. It weighs 7.25# without a rear sight and without a magazine. It has a Phantom flash suppressor. IMO it balances very well because most of the extra weight is at the rear of the barrel. It balances just forward of the center of the magwell.

I have a 18" CMMG SBR, 1:8, medium profile, rifle gas system (dissipater) with an A2 stock. It weighs close to 8# with no rear sight and no magazine. It has a Vortex flash suppressor. It balances just in front of the magwell. It feels more nose heavy than the 6721 Colt.

I am building a 16" Gov't profile, midlength, CMMG carbine with LMT collapsible stock. It should come in at about 6.2# +-. I plan to iron sight it with a Larue rear sight (saves 5 oz vs handle) and either a Phantom or Birdcage flash suppressor. My primary reason for this build is to get a 1:7 for the heavy bullets and to get away from the CAR gas system.

Added: I do not like M4 profile barrels. Unless you are planning to mount a grenade launcher or want a military look alike the 203 cut in the barrel does nothing to benefit the barrel.
 
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Does anyone make AR uppers with standard military weight barrels? All the ones I look at (Bushmaster, RRA, Stag, etc.) only show HBAR barrels on their websites.
 
Thanks. I'm looking for a lightweight barrel in a 20" upper. All the 20" uppers I see on the websites are HBAR. Bushmaster sells a 20" gov profile barrel, but not an upper made with it.
 
Oh, in 20" I am not sure any of those guys make them in the govt profile. I thought you meant in general, because they do all make M4 profile barrels. You're correct Bushmaster does make a govt profile barrel... never seen them ship that way complete though.

I would check Bravo Company or the AR15.com EE.
 
You can have the HBAR turned to your own profile and or fluted. I may choose that option over re-barreling but all the 20" flattop Colts are 1/9 twist and I'd prefer 1/7 or 1/8.
 
So are non-M4gery barrels from RRA, etc. the same thickness as the Colt HBARs I remember from the '80s/early '90s? Or does HBAR basically just mean "heavier than a government profile barrel"?
 
Many of the RRA M4 barrels are in their "R4" profile which is super-heavy under the handguards and .mil-spec M4 in front of the gas block/front sight.

RRA is now offering a lightweight M4 profile in 5.56 with chrome lining and 1/7" twist. It's been sold out since it went public, but they're making them.
 
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